Killing too much of a tumor

The traditional approach to cancer treatment has been to try to eradicate tumors. Eliminating a tumor is better than shrinking a tumor, so this approach makes sense. But if you try to eradicate the tumor and fail, you may leave the patient worse off. If you kill 90% of a tumor with some treatment but leave 10%, the remaining 10% is resistant to that treatment. You may have made the tumor more deadly by removing the weaker portions that were suppressing its growth. This explains why cancer treatments sometimes appear to be quite successful, dramatically reducing the size of tumors, without improving survival.

Sometimes one treatment will shrink a tumor as much as possible as a prelude to another treatment, such as shrinking a tumor with chemotherapy prior to surgery. But if only one treatment is being used, the situation may be like the old saying that you don’t want to wound the king. If you’re going try to kill the king, you’d better succeed.

In a recent interview on the Nature podcast, Robert Gatenby of Moffitt Cancer Center advocates an alternative approach, treating cancer as a chronic disease. Instead of killing as much of a tumor as possible, it may be better to kill as little of tumor as necessary to keep it under control. Patients would continue to take anti-cancer treatments for the rest of their lives, just as patients with heart disease or diabetes take medication indefinitely.

Related post:
Repairing tumors

6 thoughts on “Killing too much of a tumor

  1. Well, speaking as one of the latter, if I could eliminate the heart and diabetes medicine and survive I would.

  2. Sure, anyone would rather cure cancer than contain it. And Gatenby points out in his interview that we should continue to look for cures. But we should explore other alternatives and we should be aware of the potential harm of aiming for a cure and failing.

    Trying to eradicate a cancer may be like swinging for a home run. It’s great if you get it. Anyone would rather get a home run than a base hit. But an unsuccessful home run attempt is likely to be an out. Maybe we should play small ball. Of course this all depends on context. Cancer isn’t one single disease, it’s hundreds of diseases.

  3. OK, I don’t want to flood your comment spool, so here are a couple of thoughts:

    1. Diabetes, and many cardio-vascular diseases with life-long treatment, have as the underlying cause an imbalance. Eliminating the cause altogether (blood sugar, blood pressure, heart beats) would kill the patient.

    2. Other diseases with life-long treatment are only that way because there is no cure (HIV and other retro-virus infections for example).

    3. I don’t know how cancer works, but I’ve always heard that taking too little of an antibiotic would guarantee infection with resistant bacteria. Maybe just giving a little chemo to shrink a tumor would do something similar, in which case it would seem to guarantee the outcome that the novel treatment seeks to avoid — a drug-resistant tumor — but a much larger one than would likely be left over from a large chemo dose.

  4. My mother was diagnosed with breast cancer when I was 24. I thought she was crazy for not having chemo. The radiation she had left her permanently tan and changed the texture of her hair. She opted for alternative therapy and it worked very well because there has been no sign of the breast cancer since.

    In my early 30′s she was diagnosed with colon cancer. She had the tumor removed with NO RADIATION and definitely no chemo. She had to find a doctor who would do the surgery without them. She controls what is left of the colon cancer with alternative therapy and good diet. If her numbers are getting out of whack she steps up her dosage.

    Both cancers were caught early, she has a positive attitude and does aggressive research. I’m now 45 and believe my mom is alive because she is controlling the cancer. Everyone else we know who has had chemo in the same amount of time is dead. After remission the cancer would come back and it would be EVERYWHERE. Then we would prepare to say goodbye to our friends.

    Robert Gatenby of Moffitt Cancer Center is correct to advocate treating cancer this way, if at all possible. My mom has excellent quality of life. I’m glad she had the guts to take a different course. I would do the same thing if diagnosed.

  5. Prostate cancer is often treated with a containment strategy. Some varieties of the disease progress very slowly, and since surgery has a high risk of side effects, the recommended treatment may not be aggressive. One treatment option is to implant radioactive pellets to keep the tumor in check without removing it.

  6. Don’t get me wrong — there are lots of valid reasons for not using certain treatments, such as side effects of surgery, toxicity from chemo, etc. Especially if it is likely that a person will die of something else before any cancer symptoms appear, no treatment at all may be the best course, such as with many prostate cancers.

    But the proposal and the reasoning which justify it seem to be quite different than, say, avoiding surgery because of the risks of surgery per se. The analagous situation vis-a-vis surgery would be avoiding surgery because of the risk of spreading cancer as the tumor is removed, when leaving it alone might avoid that risk.

    My grandmother died from gallbladder cancer spread to her entire abdominal cavity by poor surgical practice — the surgeon didn’t bother waiting for biopsy results before removing the gallbladder, and thus didn’t take any precautions to avoid spreading cancer. Yet to this day the ACS asserts in no uncertain terms that it is a myth that cancer can be spread through surgery. When pressed they will admit privately that without special precautions it is possible, but assert that today those precautions are used universally.

    But avoiding surgery because of the risk of spreading cancer, while it also avoids the risks associated with surgery per se (death or complications due to anaesthesia, infection, blood loss, etc.), is only as reasonable as avoiding surgery because of the risk of spreading cancer.

    It is a little like saying you shouldn’t break a mirror because it will result in seven years of bad luck, while pointing out that mirror breaking can lead to lacerations of the hand.

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